Multiple sclerosis (MS) is the most common progressive neurological disease of young adults, affecting over 400,000 people in the US and over 16,000 Veterans, approximately 6,000 of whom are service connected for MS. Impaired functional mobility can be the most disabling consequence of MS, limiting independence, resulting in falls, and reducing quality of life. MS is also associated with impaired locomotor neural network functional connectivity, as demonstrated by functional magnetic resonance imaging. Preliminary data suggest that impairment of functional connectivity of the locomotor network underlies impairment of functional mobility. Our long-term goal is to develop interventions to optimize functional mobilit in people with MS (PwMS). Assistive ambulatory devices such as canes and walkers are often used by PwMS to improve functional mobility and prevent falls. However, many studies and two recent systematic reviews report that use of ambulatory assistive devices is associated with a significantly increased risk for falls in PwMS. Improper and incorrect use and lack of training with these devices likely contribute to their ineffectiveness. Although training is recommended to optimize the benefits of assistive device use, no published studies have evaluated the impact of assistive device training in PwMS or in any other population. Neuroimaging has contributed substantially to our understanding of the neural correlates of cognitive and motor dysfunction in PwMS. Task-based functional magnetic resonance imaging (fMRI) has revealed that PwMS have alterations in neural regions associated with sensorimotor functioning. Resting-state fMRI can visualize patterns of functional connectivity associated with motor functioning and has the potential to greatly expand our understanding of changes in the intrinsic functional architecture of the brain in MS and how these changes are impacted by disease progression, motor dysfunction, and rehabilitation. The goals of this research are to evaluate the impact of assistive device training on functional mobility, falls and functional neural connectivity in peopl with MS. Specifically, the objectives of this research are, in people with MS: First, to assess, ina randomized controlled trial, the impact of assistive device training on functional mobility as determined by changes in Timed Up and Go and Timed 25 Foot Walk times, 2-minute Walk distance, and Multiple Sclerosis Walking Scale-12 scores; second, to assess the impact of assistive device training on falls and fall-related injuries as determined by prospective fall diares over 18 weeks; third, to assess the impact of assistive device training on functional neural connectivity of the locomotor network as demonstrated by functional magnetic resonance imaging. We will conduct a two group randomized controlled trial at Portland VA Medical Center to compare the effectiveness of assistive device training to a wait list control condition. The assistive device training will be a standard manualized program comprised of 6 weekly one-on-one sessions with a physical therapist to include gait evaluation, device selection and fitting, an training to use the device in different environments and conditions including level and unlevel surfaces and with and without visual and auditory distractions. Program effectiveness will be assessed by comparing changes in functional mobility, falls, and functional neural connectivity of the locomotor network between the treated and the wait list control groups. We expect to find greater improvements in functional mobility and functional neural connectivity of the locomotor network and greater reduction in falls and fall related injuries in subjects randomized to assistiv device training than in subjects randomized to the wait list control condition. This pilot trial wil provide the data and experience needed for a fully powered randomized controlled trial of assistive device training in Veterans with MS.